Remote controlled flying devices are known for use in photographing or surveying operations from a position high up in the sky. In this manner it is possible to collect information to acquire such types of information, which cannot be obtained by photographing from ground surface or by surveying operation on the ground surface. US2014233099 discloses such a flying device, and further discloses an automatic take-off and landing system, having controllable light emitting elements for displaying patterns on a landing surface so as to assist in automatic take-off and landing procedures.
Other developments have aimed to use unmanned playing devices for creating aerial images in space. Literature publication Hörtner et al (2012), Spaxels, Pixels in Space—A Novel Mode of Spatial Display, (SIGMAP, page 19-24, SciTePress) describes a system using a swarm of unmanned aerial vehicles (UAVs) for creating a floating display in a three-dimensional space. Each UAV is equipped with a light source, so that it may be used as a flying pixel. The swarm of UAVs is centrally controlled by means of wireless communication between a control station and the respective drones. The positions of the respective UAVs are coordinated such that they collectively represent a three-dimensional (3D) sculpture of light nodes, wherein each UAV acts as a pixel/sample of the sculpture.